Plotting-board.



J. D. McCABE.

PLOTTING BOARD.

APPLICATION man MAR. 5. 191s.

JUNIUS D. MGCABE, 0F CORAOPOLIS, PENNSYLVANIA.

PLOTTING-BOARD.

To all whom t may concern:

Be it lmown that I, J UNIUS D. MoCABn, ak citizen of the United States,and a resident of Coraopolis, in the county of Allegheny and State ofPennsylvania, have invented a new and Improved Plotting-Board, of whichthe following is a full, clear, and exact description. l

This invention relates to a plotting device and has for an object theprovision of an improved construction whereby deed descriptions may beproperly plotted without resorting to anything except the use of apencil and paper.

Another object in view is to provide a device which may be taken to therecorders ofiice and a given piece of land properly plotted on a pieceof paper practically from the record whereby' errors in transcribingwill be eliminated.

A still further object in view is to provide an improved constructionfor laying out a piece of land from description wherein the drawing isdone within the graduations of a protractor and thereby'minimize thevarying in calculations as well as in execution.

In the accompanying drawing:

Figure 1 is a top plan view of a plotting board disclosing an embodimentof the nvention.

Fig. 2 is a section through Fig. 1 on line 2 2, the same being on anenlarged scale.

Fig. 3 is a section through Fig. 1 on line 3 3, the same being on anenlarged scale.

Fig. 4 is a detail fragmentary sectional View through Fig. 1 on line4-4, the same being on an enlarged scale.

Fig. 5 is a detail fragmentary sectional view through Fig. 2 on line5-5.

Referring to the accompanying drawing by numerals 1 indicates a basewhich may be made from wood or any other desired material on which disks2, 3 and 4 are mounted. The protractor disk 2 is provided with a centralaperture with avsupporting bearing plate 5 rigidly secured thereto byscrews or other suitable means as shown in Fig. 2, said plate snuglyfitting the cylindrical block 6 which is secured to the base 1 in anysuitable manner, as for instance by screws 7. A stationary plate 8 isrigidly secured by screws or other suitable means to the cylindricalmember 6, said plate being comparatively narrow and slidingly iitting inthe supportin guide 9 (Fig. 5) which guide is secure by screws orotherwise rigidly to the disk 3, whereby said disk is Specification ofLetters Patent.

Application led March 5, 1918. Ser1'a1 No. 220,593.

Patented Nov. 19,1918.

allowed a back and forth longitudinal movement. This movement is in alongitudinal direction and as disk 3 moves the disk 4 also may move. Inaddition to the longitudinal movement provided for disk 4 in this mannersaid disk 4 is allowed a latitudinal movement at right angles to saidlongitudinal movement. These movements both latitudinal and longitudinalare comparatively slight, but allow a proper adjustment of the disk 4beneath the paper 13 which rests on the disk 4, said adjustment beingprovided in order that lines on the paper 13 may properly register withthe directional lines 14 on disk '4. The longitudinal movement abovedescribed permits an adjustment for a major line to be brought under agiven point onl paper 13 'for the purpose of scaling the re.- quireddistance. As an example, calling the line undef the point naught, (majorlines being one inch apart) and reading to the right 250 on scale of 100to the inch,`you would count out five minor lines past the second majorline for that distance. It will of course, be understood that afractional distance would be proportioned between the minor lines. Inorder to cause this movement of disk 4 at right angles to the movementof disk 3 a tongue 29 is rigidly secured to the disk 3 as shown in Fig.3 and slidingly fits the guides 30.. Stops 31 and 32 are secured to thetongue 29 so as to limit the sliding movement of the guides and the disk4 to which they are rigidly secured.

AFrom this it will be seen that the disk 4 is substantially stationarythough allowing a slight movement in a longitudinal and a latitudinaldirection. The top disk 4 carrying directional lines minor lines 15 and16 is held against an upward movement by a number of overhangingbrackets 17 and acts as a table or supporting board for the paper 13 onwhich the drawing is to be made. This paper is held in a given positionin respect to the protractor disk 2 by a maintaining clip structure 18.This clip structure is provided with a solid plate 19 having springclips 2O thereon for gripping the paper 13 and a pair of spring members21 formed with hook sections adapted to extend through any pair ofapertures 22. Members 21 are resilient and normally are farther apartthan apertures 22, so that in order that these members may be thrustthrough these apertures they must be somewhat compressed and therebybrought under tension so that they will ordinarily remain 14 and alsothe major and

